Moisture Detection in Sensor Housing Using Embedded Resistive Sensors
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Solution Overview
Problem
Existing sensors, particularly those used in vehicles like wheel speed sensors, face reliability issues due to moisture ingress, which can lead to short-circuits and failures, as conventional housings are not effective in preventing moisture from reaching the sensor circuits, especially in damp environments.
Innovation Solution
Incorporating a moisture sensor between the sensor circuit and housing, using resistive or capacitive sensors with comb electrodes on the surface of the sensor or signal processing circuit, allowing for early detection of moisture ingress and enabling proactive countermeasures, such as transferring the vehicle to a fault operating mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a housing is used to protect the sensor circuit from moisture, then the sensor circuit is protected from penetrating moisture, but the housing itself is subject to weathering and environmental influences and is attacked by moisture over time
Solution Approach 1:
The patent applies preliminary action by incorporating a moisture sensor that detects moisture ingress before it causes damage to the sensor circuit. The moisture sensor provides early warning, allowing for preventive maintenance or countermeasures to be taken before the housing's protective capability fails completely.
Solution Approach 2:
The patent implements feedback by using the moisture sensor to continuously monitor the internal environment of the housing. When moisture is detected, the system can trigger alerts or activate heating elements to remove the moisture, creating a closed-loop system that maintains protection over the long term.
2Reliability
If a moisture sensor is added to monitor moisture ingress, then early detection of moisture is enabled, but additional installation space is required
Solution Approach 1:
The patent merges the moisture sensor with existing components on the sensor circuit board. The moisture sensor is integrated into the same housing and mounted on the circuit board alongside other electronic components, eliminating the need for separate dedicated space and reducing overall installation footprint.
Solution Approach 2:
The housing serves multiple functions: it protects the sensor circuit, provides mounting space for the moisture sensor, and acts as the sensing chamber for moisture detection. This multi-functionality reduces the need for additional components and installation space.
3Adaptability or versatility
If the sensor is used in extremely damp areas such as wheel speed sensors on vehicles, then the sensor can perform its function in these environments, but the housing cannot guarantee adequate protection against moisture ingress in the long term
Solution Approach 1:
The moisture sensor provides preliminary detection of moisture ingress in harsh environments like wheel speed sensors. By detecting moisture early in these extremely damp areas, the system can alert operators or activate countermeasures before the moisture compromises the sensor circuit's reliability.
Solution Approach 2:
The patent replaces reliance solely on mechanical sealing with an electronic monitoring system. Instead of depending only on the housing's physical barrier properties, the system uses electronic moisture sensors to detect and warn of moisture ingress, providing an additional layer of protection in challenging environments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This setup reduces the risk of safety-critical failures by detecting moisture before it affects sensor functionality, allowing for timely intervention and reducing test times during development, while maintaining the sensor's sensitivity and not requiring additional installation space.
Implementation Method 1
the moisture sensor is a resistive and/or capacitive sensor with a first electrode and a second electrode that is electrically separate from the first electrode, and an electrical resistance and/or a capacitance between the two electrodes from the one to be detected moisture dependent
Implementation Method 2
the moisture sensor is a resistive and/or capacitive sensor with a first electrode and a second electrode that is electrically separate from the first electrode, and an electrical resistance and/or a capacitance between the two electrodes from the one to be detected moisture dependent
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The invention relates to a sensor (10) for detecting a physical measuring variable with a transmitting field (30), comprising: - a sensor circuit (44) for detecting the transmitting field (30) and outputting a sensor signal (12) dependent on the physical measuring variable, - a housing (32) that at least partially encloses the sensor circuit (44), and - a moisture measuring sensor (56) between the sensor circuit (44) and the housing (32), which is configured to generate a monitoring signal (68) that is dependent on moisture penetrating between the sensor circuit (44) and the housing (32).